Field of the Invention
The present invention is generally directed toward a passive explosion isolation valve having a self-cleaning feature configured to prevent build up of debris that may adversely impact closure of the valve in the event of an energetic event.
Description of the Prior Art
Various industrial plants employ dust collection systems for removing fine particulate matter from material processing equipment in order to avoid discharge of the particulate matter into the environment. Such dust collection systems often comprise a baghouse or similar dust collection apparatus in which the particulate matter is collected prior to venting of the air stream to the atmosphere. The particulate matter collected may be highly flammable or explosive. Isolation valves are often employed to protect upstream equipment from the disastrous consequences of an explosion within the dust collection apparatus.
Isolation valves can be of the active or passive type. Active isolation valves generally require some kind of mechanical actuation in response to a detected hazardous condition, such as a deflagration wave or flame front. Active isolation valves may be of the gate valve-type, such as disclosed in U.S. Pat. No. 6,131,594, in which shifting of a gate member is effected through actuator apparatus. Another type of active isolation valve is a pinch valve, such as disclosed in U.S. Patent Application Publication No. 2013/0234054, in which an inner sleeve is compressed. As with a gate-type isolation valve, closure of the pinch valve sleeve is effected through an actuator device. Active isolation valves, while effective, are generally more complex and require the installation of detection equipment capable of identifying the onset of a hazardous energetic event and triggering the valve-closing actuator, thus resulting in increased capital cost.
Passive isolation valves, such as check valves, are generally much less complex and do not rely upon detection devices for their actuation. Rather, passive isolation valves are generally responsive to environmental changes, such as the energetic event itself or changes in pressure or direction of fluid flow. As such, passive isolation valves generally are not actively monitored to ensure their operational readiness, apart from routine inspection and maintenance. In dust collection systems, it has been discovered that accumulation of particulate matter in the vicinity of the valve may adversely impact the valve's effectiveness in preventing propagation of an energetic event. Particularly, accumulation of dust or other matter may interfere with full closure of the valve's gate member.
The present invention seeks to overcome these problems by providing a passive isolation valve configured to prevent build up of particulate matter in the vicinity of the valve closure member that could adversely affect the valve's performance in response to an energetic event.